Of increasing importance in business telephone communications is the ability to establish switched wideband connections between communicating stations. An example of such a requirement is the interconnection of both the audio and wideband portions of video communication connections. While such connections would seem at first thought to be made easily by merely adding extra communication leads to the existing switching network, such is not the case.
The problem is manyfold but in essence breaks down to the fact that the wideband portion of a connection carries communication signals sufficiently higher in frequency than conventional audio signals. These higher frequency signals cause interference unless special precautions are taken. In addition, since all stations may not be equipped with wideband facilities, it is usually uneconomical to expand the entire switching network to handle the additional communication bands necessary for wideband calls when only a relatively few stations are equipped for wideband service.
Further compounding the problem is the fact that it is not feasible to abandon existing telephone switching networks and thus, in order to effect new services, these new services must be controlled in a manner which allows them to be grafted to the existing facilities.
Thus it is an object of my invention to provide a switching network capable of handling the wideband portion of telephone interconnections without requiring modification to the existing switching network structure and without requiring complex control circuitry.
It is also an object of my invention to provide an expandable wideband switching network for use in conjunction with a conventional switching network whereby any telephone line can be equipped for wideband service.